1. Field of the Invention
The present invention relates generally to magnetic heads for hard disk drives, and more particularly to magnetic heads having a fine pitch induction coil and a shortened P2 magnetic pole yoke length, and methods for the fabrication thereof.
2. Description of the Prior Art
It is a goal of the hard disk drive industry to develop magnetic heads that provide ever faster data writing speeds, such that increased quantities of data can be written onto the hard disk in shorter periods of time. Magnetic heads commonly include write heads having two magnetic pole members, generally referred to as the P1 pole and the P2 pole (which typically includes a P2 pole tip and a yoke portion), and a flat, spiral induction coil that is fabricated between the P1 and P2 poles. Write head electrical current that passes through the induction coil creates a magnetic flux in the two magnetic pole members, and the magnetic flux passes through the write head pole tip to create a magnetic field that writes magnetic data bits onto the media, such as a hard disk, that is disposed proximate the pole tip. To improve the performance characteristics of hard disk drives, efforts have been directed to increasing the speed with which data bits can be written by the magnetic head onto the magnetic media.
One of the parameters that controls the rate at which data can be written is the rate with which magnetic flux changes can be made by the write head. This flux change rate is in part controlled by the magnetic flux rise time of the write head, and the physical geometry of the write head, particularly the P2 pole yoke length, is one of the significant parameters that determines the magnetic flux rise time. Therefore, if the magnetic flux rise time can be shortened, such as by shortening the yoke length, the data writing rate of a magnetic head can be increased.
Prior art efforts to shorten the yoke length have lead to the development of multiple layered induction coils. However, such multiple layer induction coils, as are known in the prior art, are generally difficult to reliably fabricate. Specifically, the prior art multiple layer coil fabrication methods have generally employed well known photolithographic techniques which limit the definition of the induction coil line width. In addition, it is also difficult to remove the plating seed layer between the coil turns when the coil pitch is very small. Other methods that utilize image transfer techniques have resulted in problems related to the difficulty of removing photoresist materials and/or SiO2 electrical insulation material from areas proximate the air bearing surface (ABS) of the magnetic head.
The present invention utilizes a reactive ion etching fabrication technique to achieve better physical characteristics for write head pole components including a shortening of the yoke length, whereby the magnetic flux rise time of the magnetic head is reduced, such that the data writing rate of the magnetic head is increased.